The attack is likely to raise questions as to whether aviation safety officials need to change rules about passengers travelling with guns. Handguns can legally be carried in checked baggage but must be unloaded and stored in a locked and hard-walled receptacle, according to TSA rules. Ammunition and firearms must be declared to the airline when checking baggage.

While travellers have to take off their shoes, set their carry-on luggage through X-ray machines and pass through metal detectors to reach boarding gates, many other sections of airports, such as ticket counters and luggage assert regions, are more lightly secured and vulnerable to attack.

A law enforcement official told the Associated Press that Santiago had strolled into the FBI office in Anchorage in November to say the American government was controlling his intellect and inducing him watch Islamic State videos.

Agents questioned an agitated and disjointed-sounding Santiago and then called police, who took him for a mental health evaluation, according to the official, who spoke on condition of anonymity.

George Piro, an FBI agent in charge of the Miami field office, had reaffirmed that Santiago had come into the Anchorage office and said he clearly indicated at the time that he was not intent on hurting anyone.

A military spokesperson told the Associated Press that in 2016 Santiago received a general discharge from the Alaska army national guard for unsatisfactory performance. He had joined the guard in November 2014, she said, having previously served in the army reserves.

A spokesman for the Puerto Rico national guard, Major Paul Dahlen, said Santiago was deployed to Iraq in 2010 and spent a year there with the 130 th Engineer Battalion, the 1013 th technologist company.

Santiagos brother, Bryan, told the Associated Press his brother had been receiving psychological treatment in Alaska. Santiagos girlfriend had alerted the family to the situation in recent months, he added.

Bryan Santiago said he did not know what his brother was being treated for and they had never “was talkin about a” it.

Floridas governor, Rick Scott, condemned the shooting as a senseless act of evil. He said: You only cant imagine how this could ever happen in a great state like ours. Think of the innocent lives that are lost. We still have people fighting for their lives in our hospitals.

Whoever is responsible will be held accountable to the full magnitude of the law. Let me repeat this, the country of Florida, the citizens of Florida, law enforcement, will not tolerate evil acts. My heart goes out to every family impacted. The households who lost their loved ones, and those with loved ones still in hospital fighting for their lives.

Scott, a Republican, said he had reached out to the president-elect, Donald Trump, and the vice-president-elect, Mike Pence, several times. They told me that whatever resources we needed from the federal government, they would do everything in their power to build that happen, he said.

Earlier, the sheriffs office said there was an active search for another gunman. Barbara Sharief, mayor of Broward County, told CNN police had received reports of possible shots in an airport parking garage. People were watched to scatter and run along a runway, carrying baggage.

However, at the mid-afternoon press conference, the sheriff rejected rumors of multiple gunmen. At this point, theres no second active shooter, Israel said. Theres been no shooting in any place else than in the downstairs of terminal two.

All flights were temporarily suspended. Were just going to go step-by-step, methodically through the building before we go to any steps to reopen operations, said airport director Mark Gale.

Shortly before 5pm, the sheriffs office warned that a schemed controlled detonation would take place near the airport, although it was unknown if the package related to the shooting.

Ari Fleischer, a former White House press secretary, was at the airport when the shooting passed and tweeted what he could see.

Shots have been fired, he wrote just before 1pm ET. Everyone is running. Twenty minutes later, he added: All seems calm now but the police arent letting anyone out of the airport at the least not the area where I am.

One witness told MSNBC the shooter was a slender man who was directly firing at us while passengers waited for their bags.

I put my head down and prayed, the witness said, adding that his wife had given first aid to someone who had been shot in the head. The witnesss mother-in-law tended to another victim but the person was already dead, he said.